"At just thirty-five, reclusive billionaire Robbie Malcolm is a renowned financial prognosticator, a celebrated philanthropist, and a mathematical genius. Also, he's dying, which is a fact he's carefully concealing from the world. As he takes stock, Robbie realizes that his wealth means nothing if he can't help the people who matter most. So, he invites his oldest friends--Blair, Cat, and Wade--to their beloved Fenwick Island on the coast of Delaware...